TSIS-1 SIM V11 Solar Spectral Irradiance

NASA’s Total and Spectral Solar Irradiance Sensor-1 (TSIS-1) operates on the International Space Station. TSIS-1 provides absolute measurements of the total solar irradiance (TSI) and spectral solar irradiance (SSI), important for accurate scientific models of climate change and solar variability. TSIS-1 is comprised of two instruments, the Total Irradiance Monitor (TIM), and the Spectral Irradiance Monitor (SIM).

This repository archives Version 11 (V11) of the TSIS-1 SIM Level 3 (L3) data release, and contains SSI in two cadences, 12-hour and 24-hour. The TSIS-1 SIM L3 V11 data release contains data from 2018-03-14 to 2024-01-24. TSIS-1 SIM data obtained between 2022-03-19 and 2022-05-19 were affected by an anomaly of the sun-pointing sensor (HFSS-B), which offset pointing by ~1 arcminute. V08 introduced a spectral correction for this period, and V09 introduced the ADDITIONAL_UNCERTAINTY column in the data release that reflects the additional irradiance uncertainty associated with the spectral correction.

The TSIS-1 SIM prism degradation rate on the primary channel started increasing in Spring 2023, due to increased solar activity. The V11 data release is an 'off-cycle' release (not associated with a set of semi-annual Channel C scans), specifically designed to mitigate (but not fully correct) for this increased degradation. The V12 data release is designed to fully correct for any future degradation trends (partially due to the introduction of polynomials to track degradation trends instead of exponentials).

On Sept 3, 2023, the TSIS-1 SIM instrument had a lock-up of the Digital Signal Processor (DSP). Command and control of the DSP was restored on Oct 21, 2023, however, the Electrical Substition Radiometers (ESRs) showed anomalous irradiances in certain wavebands in certain configurations. As a result, no TSIS-1 SIM L3 data longward of 1620 nm is published in V11 after Oct 21, 2023. Some additional data longward of 1620 nm is present in the V12 data release, but temporal and wavelength gaps should be expected between 1620 - 2300 nm, until corrections are available in a future data release.

See the attached TSIS_SIM_V11_Release_Notes.pdf or the TSIS SIM Data Products Release Notes page (https://lasp.colorado.edu/tsis/data/ssi-data/sim-ssi-release-notes/) for further details, and instructions for obtaining the latest TSIS-1 SIM L3 data release.

Data is archived in ASCII, netCDF, and IDL SAVfile format.

The Release Notes document (TSIS_SIM_V11.1_Release_Notes.pdf) is the 2nd version (V2) of the V11 release notes.